1. Field of the Invention
The invention relates generally to food, beverage, and personal care product additives and, more specifically, to solutions of carotenoids for use in supplementing foods, beverages, and personal care products with carotenoids and for use in coloring foods and beverages.
2. Background of the Prior Art
Carotenoids are naturally-occurring yellow to red pigments of the terpenoid group that can be found in plants, algae, and bacteria. Carotenoids include hydrocarbons (carotenes) and their oxygenated, alcoholic derivatives (xanthophylls). They include actinioerythrol, astaxanthin, bixin, canthaxanthin, capsanthin, capsorubin, β-8′-apo-carotenal (apo-carotenal), β-12′-apo-carotenal, α-carotene, β-carotene, “carotene” (a mixture of α- and β-carotenes), γ-carotene, α-cryptoxanthin, β-cryptoxanthin, lutein, lycopene, violerythrin, zeaxanthin, and esters of hydroxyl- or carboxyl-containing members thereof. Many of the carotenoids occur in nature as cis- and trans-isomeric forms, while synthetic compounds are frequently racemic mixtures. The carotenes are commonly extracted from plant materials. For example, lutein extracted from marigold petals is widely used as an ingredient in poultry feed where it adds color to the skin and fat of the poultry and to the eggs produced by the poultry. Many of the carotenes are also made synthetically; much of the commercially available β-carotene has been made through synthesis.
Carotenoids are used in the pharmaceutical industry and as ingredients in nutritional supplements, most commonly to date because of their pro-vitamin A activity. They have been extensively studied as antioxidants for protection against cancer and other human and animal diseases. Among the dietary carotenoids, the focus has been on β-carotene. More recently, research has begun to elicit the broad role that other carotenoids play in human and animal health. The xanthophylls in particular have been shown to possess strong antioxidant capabilities and may be useful in reducing the risk of disease. For example, the consumption of lutein and zeaxanthin has been identified as leading to a 57 percent reduction in age-related macular degeneration (Seddon et al., 1994. J. Amer. Med. Assoc. 272(18): 1413-1420). Lycopene has been identified as a nutrient that is active in reducing the risk of prostate cancer.
Carotenoids have also been of wide interest as a source of added color for food and drink products and many efforts have been made to attempt to use them as “natural” colorants for foods and beverages. However, their insolubility in water, their low solubility in fats and oils, high melting points, and their sensitivity to oxidation has limited their use. Until now, it was believed that the solubility of carotenoids in oils was limited to a maximum of about 0.08%. For specific carotenoids, the reported solubility reported is 0.029% for lutein in canola oil; 0.032% for lutein in soybean oil; 0.033% for lutein in safflower oil; 0.042% for lutein in corn oil; 0.004% for zeaxanthin in corn oil; 0.05-0.08% for β-carotene in “fats and oils” (www.agsci.ubc.ca/courses/fnh/410.colour/330.htm); and 0.005% for canthaxanthin in “fats and oils” (www.agsci.ubc.ca/courses/fnh/410.colour/330.htm).
Current processes for incorporating carotenoids into water-based beverages or foods involve the use of organic solvents, oils with emulsifiers, high heating, or high-shear mixing. Many of the current processes, particularly in beverages, produce a deposit of the carotenoids around the perimeter of the container in the region of the surface of the treated food or beverage, known as “ringing.” Optical clarity is a critical characteristic for many beverage compositions. Various fruit drinks, fruit juices and fortified water drinks have included terms such as “crystal clear” and “fresh” to distinguish their image and marketability. Traditionally, this clarity has been difficult to achieve when carotenoids are added to these aqueous compositions. The use of emulsifiers and oil for the incorporation of carotenoids will commonly result in cloudiness of the final aqueous composition.
Essential oils are volatile oils derived from plant material and usually carry the dominant flavor and aroma of the plant from which they are derived. The essential oils are often principally terpenes, and many contain monoterpenes, a class of terpenes containing two isoprene units and whose molecular structure contains a single saturated or unsaturated carbon ring. The essential oils are a group of oils of interest in the food and personal care industries since most are food grade and most have pleasant flavors and/or aromas. While the flavors or aromas can be strong at times, these oils can be placed into food matrices and it is possible to have the food or beverage mask the aroma. Accordingly, the identification of one or more essential oils that can solubilize a high percentage of one or more carotenoids is important as the desired amount of carotenoid can be delivered with a decreased amount of the essential oil. Of course, by using a decreased amount of the essential oil, it will be easier to mask any undesirable odor or flavor attribute. Surprisingly, essential oils were found to solubilize carotenoids at higher percentages than previously believed possible. The carotenoid/essential oil product can also be used for liposome technology as a delivery system for the carotenoid. This technology will also be good for other delivery systems that require a liquid carrier.